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Title: Scattering Neutrons along the Polyelectrolyte Complex/Coacervate Continuum

Abstract

The coil size of narrow molecular weight distribution deuterated poly(styrenesulfonate), PSS, within a polyelectrolyte complex doped with KBr was tracked across the continuum from solid to coacervate to solution using small-angle neutron scattering. Here, while PSS alone in solution exhibited the familiar and pronounced “polyelectrolyte effect” of coil shrinkage with increasing [KBr], the radius of gyration Rg of the PSS in the complex remained surprisingly constant up to 1.4 M KBr, which is close to the transition between complex and coacervate behavior. Thereafter, Rg decreased with increasing KBr, remaining slightly larger than Rg for PSS in KBr alone. Upturns in the scattering at low angle, seen for complexes in lower [KBr], are consistent with porosity, observed macroscopically as whitening of the bulk complex—a universal property of polyelectrolyte complexes. Reasons for this porosity, imaged by scanning electron microscopy, are discussed. At high q ranges, a correlation peak between deuterated coils of PSS was observed.

Authors:
ORCiD logo [1];  [1];  [1];  [1]; ORCiD logo [2]; ORCiD logo [1]
  1. The Florida State Univ., Tallahassee, FL (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Biological and Environmental Research (BER)
OSTI Identifier:
1513418
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Macromolecules
Additional Journal Information:
Journal Volume: 51; Journal Issue: 13; Journal ID: ISSN 0024-9297
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Fares, Hadi M., Ghoussoub, Yara E., Delgado, Jose D., Fu, Jingcheng, Urban, Volker S., and Schlenoff, Joseph B. Scattering Neutrons along the Polyelectrolyte Complex/Coacervate Continuum. United States: N. p., 2018. Web. doi:10.1021/acs.macromol.8b00699.
Fares, Hadi M., Ghoussoub, Yara E., Delgado, Jose D., Fu, Jingcheng, Urban, Volker S., & Schlenoff, Joseph B. Scattering Neutrons along the Polyelectrolyte Complex/Coacervate Continuum. United States. doi:10.1021/acs.macromol.8b00699.
Fares, Hadi M., Ghoussoub, Yara E., Delgado, Jose D., Fu, Jingcheng, Urban, Volker S., and Schlenoff, Joseph B. Mon . "Scattering Neutrons along the Polyelectrolyte Complex/Coacervate Continuum". United States. doi:10.1021/acs.macromol.8b00699. https://www.osti.gov/servlets/purl/1513418.
@article{osti_1513418,
title = {Scattering Neutrons along the Polyelectrolyte Complex/Coacervate Continuum},
author = {Fares, Hadi M. and Ghoussoub, Yara E. and Delgado, Jose D. and Fu, Jingcheng and Urban, Volker S. and Schlenoff, Joseph B.},
abstractNote = {The coil size of narrow molecular weight distribution deuterated poly(styrenesulfonate), PSS, within a polyelectrolyte complex doped with KBr was tracked across the continuum from solid to coacervate to solution using small-angle neutron scattering. Here, while PSS alone in solution exhibited the familiar and pronounced “polyelectrolyte effect” of coil shrinkage with increasing [KBr], the radius of gyration Rg of the PSS in the complex remained surprisingly constant up to 1.4 M KBr, which is close to the transition between complex and coacervate behavior. Thereafter, Rg decreased with increasing KBr, remaining slightly larger than Rg for PSS in KBr alone. Upturns in the scattering at low angle, seen for complexes in lower [KBr], are consistent with porosity, observed macroscopically as whitening of the bulk complex—a universal property of polyelectrolyte complexes. Reasons for this porosity, imaged by scanning electron microscopy, are discussed. At high q ranges, a correlation peak between deuterated coils of PSS was observed.},
doi = {10.1021/acs.macromol.8b00699},
journal = {Macromolecules},
number = 13,
volume = 51,
place = {United States},
year = {2018},
month = {6}
}

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Cited by: 9 works
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Figures / Tables:

Scheme 1 Scheme 1: Proposed structures of the (A) polyelectrolyte complex made from the polycation/polyanion pair PDADMA/PSS, and of the same complex as it transitions into the coacervate phase with the addition of KBr as salt. The chains in the network are hypothesized to either (B) expand while remaining connected at certainmore » polymer/polymer points with salt either closely associated with the polyelectrolyte or in the surrounding solution, or (C) phase separate into denser regions to maintain some polymer connectivity, while remaining more tightly coiled, with excess salt and water occupying an adjacent microphase. The square on the right shows how the charged repeat units are compensated by small ions or, to a lower extent, the other polyelectrolyte.« less

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Works referencing / citing this record:

Structure and Rheology of Polyelectrolyte Complexes in the Presence of a Hydrogen-Bonded Co-Solvent
journal, June 2019